J. Moore BIO 103 DB 3 and DB 4

#3

For this discussion I would like for you to explain the difference between an enzyme,  an active site, and  a substrate.  Choose a specific enzyme such as lactase and the mode of action of the enzyme.  There are several to choose from so please do not choose lactase.  In addition, provide details describing what happens when this enzyme is faulty or is not working properly.

#4

Briefly describe the relationship between photosynthesis and respiration in terms of the reactants and products of each chemical reaction.  Hypothesize why virtually every theory of mass extinctions on the planet such as the asteroid impact theory involve decreased sunlight as the source.  In your explanation, briefly explain the asteroid impact theory.  Give some thought to your study in chapter 1 of the levels of organization and how the elimination of plants would affect virtually every ecosystem on the planet, our biosphere.

PLEASE ANSWER EACH QUESTION SEPARATE